Endovascular revascularization strategies for aortoiliac and femoropopliteal artery disease: a meta-analysis.

AIMS: Optimal endovascular management of intermittent claudication (IC) remains disputed. This systematic review and meta-analysis compares efficacy and safety outcomes for balloon angioplasty (BA), bare-metal stents (BMS), drug-coated balloons (DCB), drug-eluting stents (DES), covered stents, and atherectomy. METHODS AND RESULTS: Electronic databases were searched for randomized, controlled trials (RCT) from inception through November 2021. Efficacy outcomes were primary patency, target-lesion revascularization (TLR), and quality-of-life (QoL). Safety endpoints were all-cause mortality and major amputation. Outcomes were evaluated at short-term (<1 year), mid-term (1-2 years), and long-term (≥2 years) follow-up. The study was registered on PROSPERO (CRD42021292639). Fifty-one RCTs enrolling 8430 patients/lesions were included. In femoropopliteal disease of low-to-intermediate complexity, DCBs were associated with higher likelihood of primary patency [short-term: odds ratio (OR) 3.21, 95% confidence interval (CI) 2.44-4.24; long-term: OR 2.47, 95% CI 1.93-3.16], lower TLR (short-term: OR 0.33, 95% CI 0.22-0.49; long-term: OR 0.42, 95% CI 0.29-0.60) and similar all-cause mortality risk, compared with BA. Primary stenting using BMS was associated with improved short-to-mid-term patency and TLR, but similar long-term efficacy compared with provisional stenting. Mid-term patency (OR 1.64, 95% CI 0.89-3.03) and TLR (OR 0.50, 95% CI 0.22-1.11) estimates were comparable for DES vs. BMS. Atherectomy, used independently or adjunctively, was not associated with efficacy benefits compared with drug-coated and uncoated angioplasty, or stenting approaches. Paucity and heterogeneity of data precluded pooled analysis for aortoiliac disease and QoL endpoints. CONCLUSION: Certain devices may provide benefits in femoropopliteal disease, but comparative data in aortoiliac arteries is lacking. Gaps in evidence quantity and quality impede identification of the optimal endovascular approach to IC.

Incidence, outcomes, and predictors of new heart failure in syrian conflict-affected population following hospitalization for atrial fibrillation: A retrospective cohort study.

BACKGROUND: Atrial fibrillation (AF) is the most common arrhythmia worldwide. Data regarding readmission for new congestive heart failure (CHF) following index admission for AF in the developing world are poorly described. OBJECTIVES: The study aimed to assess the rate, predictors, and outcomes of 120-day CHF readmission after index admission for AF in Syria. METHODS: This retrospective cohort study collected all adult patients without known CHF who had an index admission with AF to Latakia's tertiary center between June 2021-December 2023. Data were taken from patients' medical notes. The primary outcome included readmission with incident CHF within 120 of index discharge, and secondary outcomes included predictors and outcomes of these CHF readmissions. RESULTS: A total of 660 patients were included in the final analysis, of which 69 (11.7%) were readmitted with new CHF within 120 days of index discharge. Readmitted patients had higher median age (58 vs 70 years, p < .001). Factors that independently increased 120-day CHF incidence were age ≥60 years (HR: 9.8, 95% CI: 4.8-23.6, p < .001), diabetes mellitus (DM) (HR:2.9, 95% CI:1.7-4.9, p < .001), valvular heart disease (VHD) (HR:1.7, 95% CI:1.04-2.78, p = .047), and hypertension (HR:2.5, 95% CI:1.5-4, p < .001). Inpatient mortality occurred in six readmitted patients (9%). LVEF <40% (HR:6.7, 95% CI: 24.31, p = .01) and DM (HR:7.2, 95% CI: 1.9-33, p = .004) were independently associated with inpatient mortality. CONCLUSION: Hospitalization for new CHF was common in Syrian patients discharged with AF. The clinical predictors of incident CHF emphasize the importance of integrated management of lifestyle risk factors and common comorbidities in AF patients to optimize outcomes in resource-depleted communities.

Atrial fibrillation inpatient management patterns and clinical outcomes during the conflict in Syria: An observational cohort study.

BACKGROUND: Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide. However, there is no data on AF inpatient management strategies and clinical outcomes in Syria. OBJECTIVES: The study aims were to review the inpatient management of patients with AF and assess cardiovascular (CV) mortality in a tertiary cardiology centre in Latakia, Syria. METHODS: A single-centre retrospective observational cohort study was conducted at Tishreen's University Hospital, Latakia, Syria, from June 2021 to June 2023. Patients ≥16 years of age presenting and being treated for AF as the primary diagnosis with or without a thromboembolic event were included. Medical records were examined for patients' demographics, laboratory results, treatment plans and inpatient details. Studied outcomes include inpatient all-cause and CV mortality, ischemic and bleeding events, and conversion to sinus rhythm (SR). RESULTS: The study included 596 patients. The median age was 58, and 61% were males. 121 patients (20.3%) were known to have AF. A rhythm control strategy was pursued in 39% of patients. Ischemic and bleeding events occurred in 62 (11%) and 12 (2%), respectively. CV and all-cause mortality occurred in 28 (4.7%) and 31 patients (5%), respectively. The presence of valvular heart disease (VHD) (adjusted odds ratio (aOR) = 9.1, 95% confidence interval (CI): 1.7 to 55.1, p < .001), thyroid disease (aOR: 9.7, 95% CI = 1.2 to 91.6, p < .001) and chronic obstructive pulmonary disease (COPD) (aOR: 82, 95% CI: 12.7 to 71, p < .001) were independent risk factors of increased CV inpatient mortality. CONCLUSION: Syrian inpatients admitted with AF in Latakia are relatively younger than those in other countries. Active thyroid disease, COPD and VHD were independent risk factors of inpatient CV mortality with AF.

Can clinician's risk assessments distinguish those who disclose suicidal ideation from those who attempt suicide?

Participants were 85 individuals who made suicide attempts within two years of their Improving Access to Psychological Therapies (IAPT) assessment, identified using record linkage. Two comparison groups, non-suicidal controls (n = 1416) and (ideators, n = 743) were compared on variables extracted from the standardized IAPT risk assessment interview. Disclosure of a historical suicide attempt or non-suicidal self-injury (NSSI) distinguished those making an attempt from those with suicidal ideation only, but suicidal intent did not. A third of the participants concealed a historical suicide attempt. The IAPT Phobia Scale classified 49.30% of attempters with 100% specificity. The IAPT Phobia Scale may have clinical value in assessing risk but requires validation. Past suicide attempt and NSSI have better clinical risk assessment utility than current suicidal ideation intensity. Risk assessment relying on disclosure is likely to be flawed and risks support being withheld from those assumed to be at lower risk.

An Integrated Module Performs Selective 'On-Line' Epoxidation in the Biosynthesis of the Antibiotic Mupirocin.

The delineation of the complex biosynthesis of the potent antibiotic mupirocin, which consists of a mixture of pseudomonic acids (PAs) isolated from Pseudomonas fluorescens NCIMB 10586, presents significant challenges and the timing and mechanisms of several key transformations remain elusive.   Particularly intriguing are the steps that process the linear backbone from the initial polyketide assembly phase to generate the first cyclic intermediate PA-B. These include epoxidation as well as incorporation of the tetrahydropyran (THP) ring and fatty acid sidechain required for biological activity. Here, we show that the mini-module MmpE performs a rare online (ACP-substrate) epoxidation and is integrated ('in-cis') into the polyketide synthase via a docking domain. A linear polyketide fragment with 6 asymmetric centres was synthesised using a convergent approach and used to demonstrate substrate flux via an atypical KS0 and a previously unannotated ACP (MmpE_ACP). MmpE_ACP-bound synthetic substrates were critical in demonstrating successful epoxidation in vitro by the purified MmpE oxidoreductase domain. Alongside feeding studies, these results confirm the timing as well as chain length dependence of this selective epoxidation. These mechanistic studies pinpoint the location and nature of the polyketide substrate prior to the key formation of the THP ring and esterification that generate PA-B.

Machine learning in sudden cardiac death risk prediction: a systematic review.

AIMS: Most patients who receive implantable cardioverter defibrillators (ICDs) for primary prevention do not receive therapy during the lifespan of the ICD, whilst up to 50% of sudden cardiac death (SCD) occur in individuals who are considered low risk by conventional criteria. Machine learning offers a novel approach to risk stratification for ICD assignment. METHODS AND RESULTS: Systematic search was performed in MEDLINE, Embase, Emcare, CINAHL, Cochrane Library, OpenGrey, MedrXiv, arXiv, Scopus, and Web of Science. Studies modelling SCD risk prediction within days to years using machine learning were eligible for inclusion. Transparency and quality of reporting (TRIPOD) and risk of bias (PROBAST) were assessed. A total of 4356 studies were screened with 11 meeting the inclusion criteria with heterogeneous populations, methods, and outcome measures preventing meta-analysis. The study size ranged from 122 to 124 097 participants. Input data sources included demographic, clinical, electrocardiogram, electrophysiological, imaging, and genetic data ranging from 4 to 72 variables per model. The most common outcome metric reported was the area under the receiver operator characteristic (n = 7) ranging between 0.71 and 0.96. In six studies comparing machine learning models and regression, machine learning improved performance in five. No studies adhered to a reporting standard. Five of the papers were at high risk of bias. CONCLUSION: Machine learning for SCD prediction has been under-applied and incorrectly implemented but is ripe for future investigation. It may have some incremental utility in predicting SCD over traditional models. The development of reporting standards for machine learning is required to improve the quality of evidence reporting in the field.

Effect of serial awake prone positioning on oxygenation in patients admitted to intensive care with COVID-19.

INTRODUCTION: Awake prone positioning (APP) might benefit patients with COVID-19 by improving oxygenation, but it is unknown whether this improvement can be sustained with serial proning episodes. METHODS: We conducted a retrospective review of adults with COVID-19 admitted to one intensive care unit, in those who underwent APP and controls. Patients in both groups had type 1 respiratory failure requiring oxygen (but not initially intubated), confirmed SARS-CoV-2 PCR by nasopharyngeal swab and findings of multifocal ground-glass opacities on imaging. For the APP group, serial SpO2/FiO2 measurements were recorded after each proning episode. RESULTS: Of 77 patients admitted, 50 (65%) were excluded because they had already been intubated. Another 7 (9%) had undergone APP prior to admission. Of the remaining 20, 10 underwent APP and 10 were controls. Patients in both groups had similar demographics, subsequent intubation and survival. Of those who underwent APP, SpO2/FiO2 was most likely to increase after the first episode (before median: 152, IQR 135-185; after: median 192, IQR 156-234, p=0.04). Half of participants (5) in the APP group were unable to tolerate more than two APP episodes. CONCLUSIONS: Most patients with COVID-19 admitted to the intensive care are not suitable for APP. Of those who are, many cannot tolerate more than two episodes. Improvements in SpO2/FiO2 secondary to APP are transient and most likely in the first episode. Our findings may explain why other studies have failed to show improvements in mortality from APP despite improvements in oxygenation.

Accelerating the Evolution of Severe Acute Respiratory Syndrome Coronavirus 2: A Risk of Combining Dexamethasone and Tocilizumab for Severe Coronavirus Disease 2019.

Emerging data from open-label randomized trials without placebo controls suggest potential mortality benefits for combining corticosteroids with the interleukin 6 receptor antagonist tocilizumab in severe coronavirus disease 2019. Conversely, dual immunomodulation may weaken antiviral responses and delay viral clearance, allowing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to expand its population and accrue genetic diversity within individual hosts. Generating a pool of hosts with genetically diverse viral populations while introducing new selective pressures in the form of vaccination-induced immunity could accelerate the process of antigenic drift in SARS-CoV-2. However, clinical trials to date have largely disregarded viral outcomes, and data on viral kinetics in response to immunomodulation are scarce. Coadministration of antiviral agents with immunomodulation could serve as a potential strategy to aid viral clearance and reduce the risk of genetic diversification.

Treatment-adjusted prevalence to assess HIV testing programmes.

Scale-up of human immunodeficiency virus (HIV) testing and antiretroviral therapy (ART) for people living with HIV has been increasing in sub-Saharan Africa. As a result, areas with high HIV prevalence are finding a declining proportion of people testing positive in their national testing programmes. In eastern and southern Africa, where there are settings with adult HIV prevalence of 12% and above, the positivity from national HIV testing services has dropped to below 5%. Identifying those in need of ART is therefore becoming more costly for national HIV programmes. Annual target-setting assumes that national testing positivity rates approximate that of population prevalence. This assumption has generated an increased focus on testing approaches which achieve higher rates of HIV positivity. This trend is a departure from the provider-initiated testing and counselling strategy used early in the global HIV response. We discuss a new indicator, treatment-adjusted prevalence, that countries can use as a practical benchmark for estimating the expected adult positivity in a testing programme when accounting for both national HIV prevalence and ART coverage. The indicator is calculated by removing those people receiving ART from the numerator and denominator of HIV prevalence. Treatment-adjusted prevalence can be readily estimated from existing programme data and population estimates, and in 2019, was added to the World Health Organization guidelines for HIV testing and strategic information. Using country examples from Kenya, Malawi, South Sudan and Zimbabwe we illustrate how to apply this indicator and we discuss the potential public health implications of its use from the national to facility level.

Le dépistage du virus de l'immunodéficience humaine (VIH) et le traitement antirétroviral (TAR) pour les personnes vivant avec le VIH ont connu un véritable essor en Afrique subsaharienne. Par conséquent, les régions touchées par une forte prévalence du VIH détectent un pourcentage moins élevé de personnes testées positives dans leurs programmes de dépistage nationaux. En Afrique orientale et australe, là où certains endroits affichent une prévalence du VIH chez l'adulte égale ou supérieure à 12%, le taux de positivité des services de dépistage nationaux est passé sous la barre des 5%. Identifier les personnes nécessitant un TAR devient donc plus coûteux pour les programmes nationaux consacrés au VIH. Pour définir les objectifs annuels, on part du principe que les taux de positivité nationaux se rapprochent du taux de prévalence au sein de la population. Cette supposition a orienté les démarches vers des méthodes de dépistage permettant d'obtenir des taux de positivité plus élevés; une tendance qui s'écarte de la stratégie des services de dépistage et de conseil à l'initiative des prestataires, utilisée à l'aube de la lutte mondiale contre le VIH. Dans le présent document, nous nous intéressons à un nouvel indicateur, la prévalence ajustée sur le traitement. Cet indicateur peut servir de référence concrète pour les pays qui souhaitent évaluer le taux de positivité attendu chez l'adulte dans un programme de dépistage, en tenant compte de la prévalence du VIH au niveau national ainsi que de la portée du TAR. Le calcul consiste à enlever les personnes recevant un TAR du numérateur et du dénominateur de la prévalence du VIH. La prévalence ajustée sur le traitement peut aisément être déterminée en fonction des données de programme et estimations de population existantes. En 2019, elle a également été ajoutée aux lignes directrices de l'Organisation mondiale de la Santé pour l'information stratégique et le dépistage du VIH. En nous inspirant d'exemples issus du Kenya, du Malawi, du Soudan du Sud et du Zimbabwe, nous expliquons comment employer cet indicateur et abordons les potentielles implications liées à son utilisation en matière de santé publique, en partant du niveau national jusqu'aux établissements.

La ampliación de las pruebas de detección del virus de la inmunodeficiencia humana (VIH) y del tratamiento antirretrovírico (TAR) para las personas infectadas por el VIH ha aumentado en el África subsahariana. En consecuencia, el porcentaje de personas que dan positivo en las pruebas de detección del VIH en los programas nacionales está disminuyendo en las zonas con alta prevalencia del virus. En África meridional y oriental, donde hay entornos con una prevalencia del VIH en adultos del 12 % o superior, la tasa de positividad de los servicios nacionales de pruebas de detección del VIH ha descendido a menos del 5 %. Por lo tanto, la identificación de las personas que necesitan TAR es cada vez más costosa para los programas nacionales de VIH. El establecimiento de objetivos anuales supone que las tasas de positividad de las pruebas nacionales se aproximan a las de la prevalencia de la población. Esta suposición ha generado una mayor atención a los enfoques de las pruebas que logran tasas más altas de positividad del VIH. Esta tendencia se aleja de la estrategia del asesoramiento y las pruebas que iniciaron los proveedores y que se utilizó al principio de la respuesta mundial al VIH. Se analiza un nuevo indicador, la prevalencia ajustada según el tratamiento, que los países pueden emplear como punto de referencia práctico para estimar la tasa de positividad esperada en adultos en un programa de pruebas de detección cuando se tiene en cuenta tanto la prevalencia nacional del VIH como la cobertura del TAR. El indicador se calcula eliminando del numerador y el denominador de la prevalencia del VIH a las personas que reciben TAR. La prevalencia ajustada según el tratamiento se puede estimar con facilidad a partir de los datos de los programas existentes y de las estimaciones de población, además, en 2019, se incluyó en las directrices de la Organización Mundial de la Salud para las pruebas de detección del VIH y en la información estratégica. A través de ejemplos de países como Kenia, Malaui, Sudán meridional y Zimbabue, se demuestra cómo aplicar este indicador y se discuten las posibles implicaciones para la salud pública de su uso desde el nivel nacional hasta el de los centros.

The need for improved discharge criteria for hospitalised patients with COVID-19-implications for patients in long-term care facilities.

In the COVID-19 pandemic, patients who are older and residents of long-term care facilities (LTCF) are at greatest risk of worse clinical outcomes. We reviewed discharge criteria for hospitalised COVID-19 patients from 10 countries with the highest incidence of COVID-19 cases as of 26 July 2020. Five countries (Brazil, Mexico, Peru, Chile and Iran) had no discharge criteria; the remaining five (USA, India, Russia, South Africa and the UK) had discharge guidelines with large inter-country variability. India and Russia recommend discharge for a clinically recovered patient with two negative reverse transcription polymerase chain reaction (RT-PCR) tests 24 h apart; the USA offers either a symptom based strategy-clinical recovery and 10 days after symptom onset, or the same test-based strategy. The UK suggests that patients can be discharged when patients have clinically recovered; South Africa recommends discharge 14 days after symptom onset if clinically stable. We recommend a unified, simpler discharge criteria, based on current studies which suggest that most SARS-CoV-2 loses its infectivity by 10 days post-symptom onset. In asymptomatic cases, this can be taken as 10 days after the first positive PCR result. Additional days of isolation beyond this should be left to the discretion of individual clinician. This represents a practical compromise between unnecessarily prolonged admissions and returning highly infectious patients back to their care facilities, and is of particular importance in older patients discharged to LTCFs, residents of which may be at greatest risk of transmission and worse clinical outcomes.

Spin colossal magnetoresistance in an antiferromagnetic insulator.

Colossal magnetoresistance (CMR) refers to a large change in electrical conductivity induced by a magnetic field in the vicinity of a metal-insulator transition and has inspired extensive studies for decades1,2. Here we demonstrate an analogous spin effect near the Néel temperature, TN = 296 K, of the antiferromagnetic insulator Cr2O3. Using a yttrium iron garnet YIG/Cr2O3/Pt trilayer, we injected a spin current from the YIG into the Cr2O3 layer and collected, via the inverse spin Hall effect, the spin signal transmitted into the heavy metal Pt. We observed a two orders of magnitude difference in the transmitted spin current within 14 K of the Néel temperature. This transition between spin conducting and non-conducting states was also modulated by a magnetic field in isothermal conditions. This effect, which we term spin colossal magnetoresistance (SCMR), has the potential to simplify the design of fundamental spintronics components, for instance, by enabling the realization of spin-current switches or spin-current-based memories.

An Ion-Exchangeable MOF with Reversible Dehydration and Dynamic Structural Behavior (NH4 )2 [Zn2 (O3 PCH2 CH2 COO)2 ]⋠5 H2 O (BIRM-1).

(NH4 )2 [Zn2 (O3 PCH2 CH2 COO)2 ]⋅5 H2 O (BIRM-1) is a new metal phosphonate material, synthesized through a simple hydrothermal reaction between zinc nitrate and 3-phosphonopropionic acid, using urea and tetraethylammonium bromide as the reaction medium. In common with other metal-organic framework materials, BIRM-1 has a large three-dimensional porous structure providing potential access to a high internal surface area. Unlike most others, it has the advantage of containing ammonium cations within the pores and has the ability to undergo cation exchange. Additionally, BIRM-1 also exhibits a reversible dehydration behavior involving an amorphization-recrystallization cycle. The ability to undergo ion exchange and dynamic structural behavior are of interest in their own right, but also increase the range of potential applications for this material. Here the crystal structure of this new metal phosphonate and its ion exchange behavior with K+ as an exemplar are studied in detail, and its unusual structure-reviving property reported.

Tunable Sign Change of Spin Hall Magnetoresistance in Pt/NiO/YIG Structures.

Spin Hall magnetoresistance (SMR) has been investigated in Pt/NiO/YIG structures in a wide range of temperature and NiO thickness. The SMR shows a negative sign below a temperature that increases with the NiO thickness. This is contrary to a conventional SMR theory picture applied to the Pt/YIG bilayer, which always predicts a positive SMR. The negative SMR is found to persist even when NiO blocks the spin transmission between Pt and YIG, indicating it is governed by the spin current response of the NiO layer. We explain the negative SMR by the NiO "spin flop" coupled with YIG, which can be overridden at higher temperature by positive SMR contribution from YIG. This highlights the role of magnetic structure in antiferromagnets for transport of pure spin current in multilayers.

Burden and characteristics of HIV infection among female sex workers in Kampala, Uganda - a respondent-driven sampling survey.

BACKGROUND: Sex workers in Uganda are at significant risk for HIV infection. We characterized the HIV epidemic among Kampala female sex workers (FSW). METHODS: We used respondent-driven sampling to sample FSW aged 15+ years who reported having sold sex to men in the preceding 30 days; collected data through audio-computer assisted self-interviews, and tested blood, vaginal and rectal swabs for HIV, syphilis, neisseria gonorrhea, chlamydia trachomatis, and trichomonas vaginalis. RESULTS: A total of 942 FSW were enrolled from June 2008 through April 2009. The overall estimated HIV prevalence was 33% (95% confidence intervals [CI] 30%-37%) and among FSW 25 years or older was 44%. HIV infection is associated with low levels of schooling, having no other work, never having tested for HIV, self-reported genital ulcers or sores, and testing positive for neisseria gonorrhea or any sexually transmitted infections (STI). Two thirds (65%) of commercial sex acts reportedly were protected by condoms; one in five (19%) FSW reported having had anal sex. Gender-based violence was frequent; 34% reported having been raped and 24% reported having been beaten by clients in the preceding 30 days. CONCLUSIONS: One in three FSW in Kampala is HIV-infected, suggesting a severe HIV epidemic in this population. Intensified interventions are warranted to increase condom use, HIV testing, STI screening, as well as antiretroviral treatment and pre-exposure prophylaxis along with measures to overcome gender-based violence.

Sexually transmitted infections associated with alcohol use and HIV infection among men who have sex with men in Kampala, Uganda.

OBJECTIVES: Few studies have been conducted in Africa to assess prevalence of sexually transmitted infections (STIs) and risk factors among men who have sex with men (MSM). We report findings from the first behavioural survey to include STI testing among MSM in Kampala, Uganda. METHODS: Respondent-driven sampling (RDS) was used to recruit MSM for a biobehavioural survey. Eligible participants were men who reported anal sex with another man in the previous 3 months, were 18 years or older, and resided in Kampala. Information was collected on demographics, sexual behaviour, alcohol and drug use, and STI symptoms. Blood, urine and rectal specimens were tested for syphilis, HIV, rectal and urethral gonorrhoea, and chlamydia. Analyses weighted for RDS were conducted to assess associations with STI diagnosis. RESULTS: A total of 295 MSM participated in the survey. Almost half (weighted percentage: 47.3%) reported STI symptoms in the last 6 months and 12.9% tested HIV-positive. Prevalence of non-HIV STI was 13.5%; syphilis prevalence was 9.0%. Adjusting for age and education, STI was associated with HIV (adjusted OR (AOR)=3.46, 95% CI 1.03 to 11.64), alcohol use before sex (AOR=4.99, 95% CI 1.86 to 13.38) and having sold sex in the last 3 months (AOR=3.17, 95% CI 1.25 to 8.07), and inversely associated with having anonymous sex partners (AOR=0.20, 95% CI 0.07 to 0.61). CONCLUSIONS: We observed high levels of self-reported STI symptoms and STI prevalence associated with alcohol use and HIV among MSM in Kampala. Public health interventions supporting MSM are needed to address STI risk and facilitate access to diagnosis and treatment services.

Static and Dynamical Properties of Antiferromagnetic Skyrmions in the Presence of Applied Current and Temperature.

Skyrmions are topologically protected entities in magnetic materials which have the potential to be used in spintronics for information storage and processing. However, Skyrmions in ferromagnets have some intrinsic difficulties which must be overcome to use them for spintronic applications, such as the inability to move straight along current. We show that Skyrmions can also be stabilized and manipulated in antiferromagnetic materials. An antiferromagnetic Skyrmion is a compound topological object with a similar but of opposite sign spin texture on each sublattice, which, e.g., results in a complete cancellation of the Magnus force. We find that the composite nature of antiferromagnetic Skyrmions gives rise to different dynamical behavior due to both an applied current and temperature effects.

Thermal Spin Dynamics of Yttrium Iron Garnet.

The magnetic insulator yttrium iron garnet can be grown with near perfection and is therefore and ideal conduit for spin currents. It is a complex material with 20 magnetic moments in the unit cell. In spite of being a ferrimagnet, YIG is almost always modeled as a simple ferromagnet with a single spin wave mode. We use the method of atomistic spin dynamics to study the temperature evolution of the full spin wave spectrum, in quantitative agreement with neutron scattering experiments. The antiferromagnetic or optical mode is found to suppress the spin Seebeck effect at room temperature and beyond due to thermally pumped spin currents with opposite polarization to the ferromagnetic mode.

University students and the risk of HIV and other sexually transmitted infections in Uganda: the Crane survey.

Adolescents and young adults are at high risk of human immunodeficiency virus (HIV) infection in sub-Saharan Africa. Previous reports have found that university students in Africa comprise a sexually active population, although the prevalence of HIV or sexually transmitted infections (STI) has not been measured. We conducted a cross-sectional survey of students from five large universities in Kampala, Uganda, using respondent-driven sampling. We asked students to complete behavioral questionnaires and provide biological samples to test for HIV, Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum, Trichomonas vaginalis, and bacterial vaginosis. We enrolled 649 students and obtained interpretable data from 640. Around 50% of the respondents were male, and the mean age was 22 years. An estimated 0.8% (95% CI 0.0-2.0) of male students had Chlamydia infection, approximately 4.3% (95% CI 2.0-7.0) had syphilis, 0.4% (95% CI 0.0-0.9) had HIV, and none had gonorrhea. An estimated 32.6% (95% CI 22.4-40.8) of women had bacterial vaginosis, 2.5% (95% CI 0.7-6.3) had Chlamydia infection, 1.7% (95% CI 0.5-3.6) had syphilis, 1.0% (95% CI 0.0-2.4) had gonorrhea, 0.9% (95% CI 0.0-4.2) had trichomoniasis, and 0.9% (95% CI 0.0-1.8) had HIV. We found no significant risk factors for HIV or other STI among males. We also found that not using a condom during the latest sexual intercourse was significantly associated with HIV infection, other STI, or bacterial vaginosis (OR 2.16; 95% 1.26-3.78) among females. We conclude that while university students are sexually active and there is substantial risk for syphilis, there is little evidence of substantially increased HIV risk among them.